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PORTABLE BLAGKBOARD,

' Patented Jan. 5, 1897.

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W. L. SINTON. `1=0RTABLE BLAGKBOARD. No. 574,635. Patented Jan. 5, 1897.

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VALTER L. SINTON, OF TORONTO, CANADA, ASSIGNOR TO THE COMPARA- TIVE SYNOPTICAL CHART COMPANY, LIMITED, OF SAME PLACE.

PORTABLE BLACKBOARD.

SPECIFICATION forming part of Letters Patent No. 574,635, dated J' anuary 5, 1897.

Application led August 21, 1896. Serial No. 603,518. (No model.)

To all whom, t may concern.'

Be it known that I, WALTER LYON SINTON, gentleman, of the city of Toronto, in the county of York and Province of Ontario, Canada, have invented certain new and useful Improvements in Portable Blackboards, of which the following is a specification.

The object of my invention is to devise a simple and convenient portable blackboard xo especially adapted for teaching history according to Scat'fes Comparative and Synopttcal System; and it consists, essentially, of a blackboard detachably connected to a knockdown frame or easel and provided with a vertical sliding straight-edge having a changeable scale connected thereto, substantially as hereinafter more particularly.described and then definitely claimed.

Figure l is a perspective view of a blackzo board constructed in accordance with my invention. Fig. 2 is a side elevation of the same. Fig. 3 is an enlarged sectional view of the blackboard proper. Fig. 4 is a plan view of the top of a blackboard. Fig. 5 is a detail showing the cross-bar of the frame and its mode of connection to the standards.

In the drawings like letters of reference indicate corresponding parts inthe different gures.

3o A are feet suitably shaped to rest on the floor and which may also, if desired, be provided with casters.

B are two standards having jaws a formed at their lower ends, which jaws embrace the 3 5 feet A and are connected thereto by screws or pins, as shown.

S are supports formed on the standards to receive the lower edge of the blackboard D. These supports may be either formed by the projecting part of the standard, as shown, or by a pin or other device connected thereto.

C is a cross-bar having hooked metal lugs l) connected to its ends.

I are plates slotted at el and connected to the sides of the standards B, overlying recesses formed therein. The slots d are of the cross bar.

standards above the supports S are preferably, though not necessarily, tapered.

E are loops secured to the upper edge of the blackboard and adapted to embrace the up- 5 5 per ends of the standards B, as shown, when the blackboard is resting on the supports S.

A small retaining-piece c is preferably connected to the front of each support S to prevent the lower edge of the blackboard being 6o accidentally drawn off the support, though the same effect would be obtained by grooving the upper edge of the support.

II are guideways preferably shaped as shown in cross-section to reduce the frictional surfaces and connected,respectively,to thetop and bottom of the face of the blackboard. In these guideways two heads J are adapted to slide. These heads are connected by a vertical straight-edge G; 7o

f are slight recesses formed in the heads J, so that the ends of the scale K may be sprung therein. The center of the scale may be secured to the vertical straight-edge by means of a hand-screw L, which also serves as a 7 5 handle to move the vertical strai ght-ed ge with its connected scale. v

When it is desired to knock down the blackboard for transportation, the blackboard proper is lifted from the support S and the 8o loops E disengaged from. the upper ends of the standards. The cross-bar C is then removed by disengaging its hooked lugs from the plates I. Then the standards may be disengaged from the feet A by removing the connecting pins or screws, and the blackboard may then be packed together ready for shipment or removal to a new situation. By reversing the process the blackboard may be again put into condition for use. 9o

This blackboard is intended largely for use with a system of teaching history known as Scat'fes Comparta/ve and Sg/noptt'cal Historical Charts, in which the dates of historical facts or events are graphically indicated and located on said charts according to the years in which the events or facts occurred. Hence the time of Jacques Cartier and Archbishop Cranmer, for instance, would be indicated in the relative positions shown in Fig. 1 of the 10o drawings, because they are each on a line representing the same period of time. The

scale shown in my drawings is therefore one of years, each division of Which represents a period of live years.

By placing a crayon against a division on the scale representing any particular year and holding the chalk firmly against the straight-edge while the latter is moved in a horizontal direction a line may be drawn across the board indicating any particular year. Vertical lines may be drawn by drawing the chalk longitudinally along the straightedge. By these two actions parallelograms, such as shown on the board, may be constructed and filled in With the names of personages, Wars, or various historical periods.

The value of the blackboard and scale in constructing diagrams showing contemporaneous events in the history of different countries is Well illustrated by the examples shown, Where various facts and events in Canadian and English history are shown side by side. The unit ot' the scale L of years maybe made by one, five, ten, or any desired number of years, so that contemporaneous events may be presented on varying scales as may be deemed advisable. As the scales are removable, the year-scale may be detached and an ordinary scale of feet and inches substituted for making rough plans to scale, or scales indicating varying number of feet to the inch may be placed on the straight-edge for making drawings to any desired scale. Thus the blackboard may be made of use to architects for designing purposes or for various other forms of geometrical or mechanical drawing.

I am aware that blackboards have been made with vertically-sliding straight-edges, but in such there is friction at either side, and they are therefore liable to jam or Wabble,but with my horizontally-slidin g straightedge the friction is almost entirely on the lower guide, and that,as previously described, has its lower frictional surface largely reduced in area, so that a slight touch or push will send the vertical straight-edge from one end of the board to the other, thus overcoming the above difficulty Without the use of roller or ball bearings.

From the above description it will be seen that I have devised a very simple and convenient portable blackboard Well adapted for the use of teachers, architects, and draftsmen ot all kinds.

That I claim as my invention is- 1. In an article of the class described, the frame or easel comprising the feet A7 detachable standards B, provided With the supports S and detachable cross-bar C, in combination with the blackboard I) resting on the supports S and provided with the loops E, adapted to fit over the upper ends of the standards, substantially as and for the purpose specied.

2. In an article of the class described, the frame or easel comprising the feet A, detachable standards B, provided with the supports S and detachable cross-bar C, in combination with the blackboard D,rest in g on the supports S, and provided with the loops E, adapted to iit over the upper ends of the standards, and having a vertical straight-edge G movable in guideways II, connected to the front of the board, substantially as and for the purpose specified.

3. In an article of the class described, thc frame or easel comprising the feet A, the standards B, provided with the supports S, and with jaws a embracing the feet A and connected thereto by screws or pins, the crossbar C provided With hooked lugs ZJ engaging with the slotted plates I, connected to the sides of the standards I3, and overlying recesses therein, in combination With the blackboard D resting on the supports S and provided With the loops E adapted to fit over the upper ends of the standards, substantially as and for the purpose specified.

4:. In an article of the class described, thc blackboard D, having horizontal guideways I-I connected thereto shaped in section substantially as shown, in combination with the heads .I adapted to slide in the guideways, the straight-edge G connected to the heads and a scale K sprung into the recesses f in the heads J, and secured to the straight-edge by the hand-screw L, substantially as and for the purpose specified.

Toronto, June 24, 1896.

VALTER L. SIN TON.

In presence of- A. M. NEFF, FREDK. CLARKE 

